PURPOSE: The present study was designed to investigate the impact of pressure on nuclear DNA integrity in viable cells of mouse blastocysts.METHODS: The blastocysts of hybrid F1 females [(C57Bl/10 J × CBA-H);N = 15] aged 2-3 months were exposed into the pressure impulse lasting ~0.021 s and characterized by a positive pressure peak of ~76 mmHg. The nuclear DNA fragmentation index of mouse blastocysts was assessed by TUNEL assay within 60 s after exposure to pressure impulse.RESULTS: The mean nuclear DNA fragmentation index was significantly higher in the experimental group (83%) than in the control group (19.7%); p < 0.001.CONCLUSION(S): A low magnitude pressure impulse can induce nuclear DNA fragmentation in mouse blastocysts. The compression and decompression forces appearing during pressure fluctuations are responsible for the observed DNA shearing.